Dual substrate laminate-configured optical channel for multi-fiber ribbon form factor-compliant integrated multi-channel optical amplifier

Abstract

A multi-fiber ribbon-coupled multi-channel, optical amplifier architecture has a very compact form factor that facilitates one-for-one alignment with and coupling to each optical fiber of a multi-fiber ribbon. A dual substrate structure contains a first substrate having a signal transport core laminated with a second substrate having an associated pumping energy-receiving, pseudo-cladding layer. This use of separate substrates prevents dopant material of the signal transport core from intruding into the pseudo-cladding material. The bulk layers are polished and laminated so that the signal transport core is in intimate face-to-face abutment with the pseudo-cladding layer. The back side of the bulk containing the pseudo-cladding material is lapped and polished to expose pseudo-cladding material, and provide a generally planar surface that facilitates coupling of the pseudo-cladding layer (and its abutting core) with a pumping energy source.

What is claimed  
     
       1. A multi-fiber ribbon-coupled optical amplifier comprising: 
       a multi-channel optical waveguide structure having a plurality of optical waveguide amplifier channels arranged to be optically coupled with respective ones of a plurality of optical fibers of a multi-fiber ribbon over which respective light beam signals are transportable; and  
       a multi-channel optical interface configured to couple optical energy supplied by a plurality of optical pumping sources into respective ones of said plurality of optical waveguide amplifier channels of said multi-channel optical amplifier from a direction that is generally spatially transverse to said optical waveguide amplifier channels, so as to provide optical energy amplification of said respective light beam signals traveling through said optical waveguide amplifier channels of said multi-channel optical waveguide structure; and wherein  
       said multi-channel optical waveguide structure comprises a first substrate in which are formed a plurality of spatially adjacent signal transport regions that are doped with material that is effective to absorb optical pumping energy coupled thereto, and an abutting second substrate in which are formed a plurality of spatially adjacent pseudo-cladding pumping energy receiving regions, that are exclusive of said material doped that is effective to absorb optical pumping energy with which said optical signal transport regions are doped, and which respectively adjoin said signal transport regions, and wherein a surface of a respective one of said pseudo-cladding pumping energy receiving regions spaced apart from an adjoining signal transport region is configured to receive optical energy supplied by one or more of said optical pumping sources, whereby said optical energy is transferred into said pseudo-cladding region and transferred therefrom and absorbed by its adjoining signal transport region, so as to provide optical energy amplification of a respective light beam signal traveling therethrough.  
     
     
       2. A multi-fiber ribbon-coupled optical amplifier according to  claim 1 , wherein said surface of a respective one of said pseudo-cladding pumping energy receiving regions is planarized. 
     
     
       3. A multi-fiber ribbon-coupled optical amplifier according to  claim 1 , further comprising a multi-fiber ribbon input coupler adapted to optically couple light beam signals traveling through respective ones of a plurality of input optical fibers of a multi-fiber ribbon with respective ones of said optical waveguide amplifier channels of said multi-channel optical waveguide structure. 
     
     
       4. A multi-fiber ribbon-coupled optical amplifier according to  claim 1 , further comprising a multi-fiber ribbon output coupler adapted to optically couple amplified light beam signals traveling through respective ones of said plurality optical waveguide amplifier channels of said multi-channel optical waveguide structure with respective ones of a plurality of output optical fibers of a multi-fiber ribbon. 
     
     
       5. A multi-fiber ribbon-coupled optical amplifier according to  claim 1 , wherein said multi-channel optical interface includes an array of diffractive optic elements. 
     
     
       6. A multi-fiber ribbon-coupled optical amplifier according to  claim 5 , wherein said multi-channel optical interface comprises a prism-configured optical energy coupler having a plurality of optical energy focusing elements upon which optical outputs emitted by said plurality of optical pumping sources are incident, and which are operative to focus energy of said optical outputs through said prism and coupled into said truncated unclad optical fibers of said multi-channel optical amplifier. 
     
     
       7. A multi-fiber ribbon-coupled optical amplifier according to  claim 1 , wherein said multi-channel optical interface includes a plurality of GRIN lenses upon which optical outputs emitted by said plurality of optical pumping sources are incident, and which are operative to focus energy of said optical outputs emitted by said plurality of optical pumping sources into said truncated unclad optical fibers of said multi-channel optical amplifier. 
     
     
       8. A multi-fiber ribbon-coupled optical amplifier according to  claim 1 , wherein said multi-channel optical interface includes an array of focusing lenslets upon which optical outputs emitted by said plurality of optical pumping sources are incident, and which are operative to focus energy of said optical outputs emitted by said plurality of optical pumping sources into said truncated optical fibers of said multi-channel optical amplifier. 
     
     
       9. A method of making a multi-channel optical waveguide structure comprising the steps of: 
       (a) providing a first support substrate having a first surface, in which are formed a plurality of spatially adjacent optical signal transport regions doped with material that is effective to absorb optical pumping energy coupled thereto and thereby optically amplify optical signals transported thereby;  
       (b) providing a second support substrate having a first surface, in which are formed a plurality of spatially adjacent optical pumping energy transporting pseudo-clad regions that are exclusive of said material doped that is effective to absorb optical pumping energy with which said optical signal transport regions are doped;  
       (c) laminating said first and second support substrates together such that respective ones of said plurality of spatially adjacent optical signal transport regions in said first support substrate adjoin respective ones of said plurality of spatially adjacent optical pumping energy transporting pseudo-clad regions in said second support substrate; and  
       (d) removing material of said second support substrate to expose said pseudo-cladding regions and provide a generally planar surface therein that facilitates coupling of a respective pseudo-cladding region with an associated pumping energy source.  
     
     
       10. A method according to  claim 9 , further including the step (e) of removing additional material of said second support substrate to expose portions of said pseudo-cladding regions other than said generally planar surface thereof.